What other tests are indicated in the workup of pediatric atopic dermatitis (AD)?

Updated: Jun 03, 2020
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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Answer

Prick skin testing to common allergens can help identify specific triggers of atopic dermatitis. For accuracy, antihistamines must be discontinued for 1 week and topical steroids for 2 weeks prior to testing. Although skin tests are used most often in young children with moderate-to-severe disease, false-negative and false-positive test results are not uncommon in children younger than 8 years. If positive, these tests do not necessarily indicate clinically significant triggers. Prick skin tests only indicate that the patient has been sensitized to particular antigens. For example, most children shown to have multiple food allergies by skin tests only demonstrate clinically detectable allergic reactions to 3 or fewer foods when tested by double-blind randomized provocative testing.

Radioallergosorbent test (RAST) and enzyme-linked immunosorbent assay (ELISA) in vitro tests identify serum IgE directed toward specific allergens (allergen-specific IgE). As with prick skin tests, these diagnostic methods show a poor predictive value for clinically significant food allergies and may produce false-positive results when the patient's serum contains elevated nonspecific (or total) IgE levels.


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